Ethanol in petrol

We all know that alcohol and driving don't mix. Your performance as a driver is impaired by alcohol, and the same is true for your car. But while acceptable limits for drivers are well known, just how much ethanol is okay for your car to consume is apparently uncertain.

Ethanol in petrol is a hot issue, with a crossfire of claim and counter-claim from supporters and critics. Who to believe? Are the ethanol evangelists, who insist it's good for the environment, good for struggling cane farmers, and a great way to reduce the nation's dependence on fossil fuels, correct? Or do the unbelievers, who maintain that the benefits are largely illusory, and that ethanol-laced fuel brings considerable risks, have a point? Let's look at the facts...

Many of you have already run your car on a mix of petrol and ethanol. Maybe you were aware of the fact, maybe you weren't.

Among the major oil companies, BP is leading the way with ethanol. Since May 2002, it has trialled 90/10 petrol and ethanol blends in six Brisbane service stations. The company claims it has sold seven-million litres of blended ethanol without a single technical problem.

BP says it strongly supports the capping of ethanol content at 10 percent, and is in favour of pumps carrying signage advising consumers of the fuel's alcohol level. The company invested in modifying its Bulwer Island refinery in Queensland to address technical problems with mixing petrol and ethanol. BP buys ethanol made in Brisbane from the by-products of Queensland sugar cane.

Oil company giants like BP aren't the problem. Instead, it's independent fuel retailers who dilute petrol with more than 10 percent ethanol, and conceal the fact. Greed is the motivation. They make more money because ethanol production isn't taxed like petrol.

According to Australian Institute of Petroleum executive director Bryan Nye, blending 20 percent ethanol cuts between two and four cents a litre from the wholesale price of a litre of petrol. While excise is paid on ethanol, as it is on petrol, the 38-cents-per-litre tax is exactly matched by the 38-cents-per-litre Federal Government subsidy for ethanol producers, introduced last year.

Australia's largest ethanol producer is the Manildra Group, a grain-business giant. Since 1992 it has produced ethanol from the waste stream of its factory at Bomaderry, near Nowra on the NSW south coast. The factory's prime role is to extract starch, gluten, and other useful products from wheat. About two-thirds of the 60-million litres of ethanol produced by Manildra each year is blended with petrol.

Businessman Dick Honan, head of the Manildra Group, has donated large amounts to the Liberal Party, as well as smaller sums to Labor and the Democrats. Interviewed by ABC radio's AM program last October, Honan denied that donations were intended to influence the government.

"This government can't be bought at all," Honan said. "We are not in the business of trying to buy favours."

Last year Manildra went into the petrol business. In a joint venture with a privately owned oil company called Park Petroleum, it formed Manildra Park Petroleum. This company claims to be the largest supplier of blended petrol/ethanol to independent fuel retailers in the Sydney and Wollongong regions.

When, last October, the Sydney Morning Herald commissioned an analysis of petrol sold by nine independent outlets in the Sydney's south and south west, it found samples from three contained more than 20 percent ethanol, and three others more than 10 percent. Most of the six retailers were reportedly unwilling to comment to the SMH, but two named Manildra as their supplier.

Above 10 percent ethanol, you enter the danger zone. Ethanol is both corrosive and a solvent. It eats away at fuel lines and fuel-delivery-system components. It can also loosen gunk in fuel lines, leading to blockages, and in older engines - especially those with carburettors - lead to cold-start problems and misfiring.

Keep it at 10 percent and the vehicle manufacturers are reasonably happy, although you'll get slightly decreased fuel economy. On top of this, ethanol's environmental credentials turn out to be rather dubious. Theoretically, ethanol should burn a little cleaner than petrol and generate less carbon dioxide. The reality, according to CSIRO (Commonwealth Scientific and Industrial Research Organisation), is that the differences in tailpipe hydrocarbon emissions between premium unleaded and premium unleaded with the 10 percent ethanol are negligible.

The same CSIRO study also found that the carbon-dioxide emissions are marginally lower. But what the study didn't say is that these tailpipe gains are potentially offset by the high CO2 penalty levied in growing the grain or sugar to make the ethanol.

A 2001 study by Cornell University in the US found that growing an acre of corn for conversion to ethanol required 529 litres of fossil fuels. Similar studies on the energy consumption of the sugar-to-ethanol process haven't been done. The same Cornell study, again based on corn conversion, found that 70 percent more energy is needed to produce 3.8 litres (1 US gallon) of ethanol than is contained in the ethanol itself.

Put it all together and there aren't many good reasons for adding it to petrol. Car manufacturers aren't keen on it, even though they are reluctant to go on record saying it, while the environmental costs appear much higher than the sugar-cane growers, ethanol producers, and both groups' supporters in parliament will own up to.

What can the motorist do? Our recommendation is to buy from the major brands. BP, for instance, guarantees the quality of the fuel sold under its name. If fuel bought from the company can be shown to have caused a problem, BP will pay to have affected parts replaced. If you must buy from independent retailers, seek an assurance that their products are ethanol-free. If their answer is unconvincing or they can't tell you, don't buy.

THEY GO TO RIO
Among Australia's four car makers, Holden has unique ethanol expertise. It exports small numbers of Chevrolet Omega-badged Commodores to Brazil, where the cars must run on E22 fuel, a blend containing 22 percent ethanol.

This 22 percent ethanol content of Brazilian fuel is similar to the proportion discovered in 'petrol' being sold by unscrupulous retailers in the Sydney and Wollongong areas in late 2002.

Here are the modifications Holden makes to cars exported to Brazil:

So where does this leave Australian Commodore drivers, whose cars have not been ethanol-proofed? Holden's official response to the ethanol question is similar to that of other car makers. "Holden has consistently said that an ethanol blend of up to 10 percent is acceptable. Holden owners' handbooks clearly state that using fuel other than that specified (91 octane) may seriously damage the engine and may void warranty."

WHAT IS ETHANOL?
Yeast really is a remarkable little beast. Add some to a can of home-brew mix, throw in some sugar and water, and after a couple of weeks you've got beer. The sugar is converted into ethanol by the yeast, and we all know what the result of that process leads to!

The same basic principle (with some refinement) is used to make pure ethanol, which tastes nothing like beer. You take molasses, which is derived from sugar, and ferment it with yeast and some enzymes. Leave it for a week or two and drain off the liquid, which is then refined by a distillation process.

Repeat the distillation process a couple of times and you're left with pure ethanol and a whole lot of sludge, which is perfect for animal feed or for using in vitamin B-rich foods like Vegemite.

Pure ethanol looks just like vodka, only it tastes worse and smells like sweet corn. It's possible to build your own still to make the stuff, but you'll need lots of sugar, potatoes or even wheat, and your neighbours will get tired of the overwhelming stench. It's also illegal.

Pure ethanol (chemical formula C2H5OH) has an octane rating of 115, while Australian pump petrol comes in grades from 91 to 98.

The density of ethanol, 0.79kg per litre, is slightly greater than petrol. But its energy content is significantly less. Burning a kilogram of ethanol yields only 63 percent of the heat that burning the same amount of petrol would deliver.

What's more, ethanol combustion requires a quite different fuel-to-air ratio. Completely burning a kilogram of petrol needs almost 15kg of air, but a kilogram of ethanol needs exactly 9kg of air to burn entirely.

It's for these reasons that fuel efficiency declines when a blend of petrol and ethanol is used in an engine designed to run on petrol. To use ethanol efficiently means employing a higher compression ratio to make the most of its high octane number.

A greater problem is that fuel and air metering, set up for petrol, is thrown out by ethanol's different characteristics. The higher the ethanol content, the worse it gets.

Words: John Carey & Josh Gliddon